revert buffer api change

common/alloc/buffer.go

@@ -20,16 +20,14 @@ type Buffer struct {
 	pool   Pool
 	Value  []byte
 	offset int
-	startingOffset int
 }
 
-func CreateBuffer(container []byte, offset int, parent Pool) *Buffer {
+func CreateBuffer(container []byte, parent Pool) *Buffer {
 	b := new(Buffer)
 	b.head = container
 	b.pool = parent
-	b.Value = b.head[offset:]
+	b.Value = b.head[defaultOffset:]
-	b.offset = offset
+	b.offset = defaultOffset
-	b.startingOffset = offset
 	return b
 }
 
@@ -49,14 +47,14 @@ func (b *Buffer) Release() {
 // Clear clears the content of the buffer, results an empty buffer with
 // Len() = 0.
 func (b *Buffer) Clear() *Buffer {
-	b.offset = b.startingOffset
+	b.offset = defaultOffset
 	b.Value = b.head[b.offset:b.offset]
 	return b
 }
 
 // Reset resets this Buffer into its original state.
 func (b *Buffer) Reset() *Buffer {
-	b.offset = b.startingOffset
+	b.offset = defaultOffset
 	b.Value = b.head[b.offset:]
 	return b
 }
@@ -221,5 +219,5 @@ func NewBuffer() *Buffer {
 //}
 
 func NewLocalBuffer(size int) *Buffer {
-	return CreateBuffer(make([]byte, size), defaultOffset, nil)
+	return CreateBuffer(make([]byte, size), nil)
 }

common/alloc/buffer_pool.go

@@ -36,7 +36,7 @@ func (p *BufferPool) Allocate() *Buffer {
 	default:
 		b = p.allocator.Get().([]byte)
 	}
-	return CreateBuffer(b, defaultOffset, p)
+	return CreateBuffer(b, p)
 }
 
 func (p *BufferPool) Free(buffer *Buffer) {